Critical thinking question: Be able to explain the advantages of a seed over a spore in the following circumstance:

Critical thinking question: Be able to explain why a moss plant cannot grow large. How does the lack of a vascular system limit the size in which the plant can grow? Put your answer here: Critical thinking question: Be able to explain the advantages of a seed over a spore in the following circumstance: Both a seed and spore land on the ground but leaf litter prevents either of them from direct contact with the soil. The seed grows into a plant while the spore perishes. Explain why: Critical thinking question: All life forms on earth produce offspring by a process that is usually called sexual reproduction. In some asexual reproduction occurs for a time but is always followed by sexual reproduction. In asexual reproduction the result are offspring that are exactly the same as the original… they are said to be clones. This form of reproduction has major disadvantages to the species when the environment changes dramatically. Sexual reproduction on the other hand produces offspring that are not identical to either of the parents because they a mixture of both parent’s genes. What are the disadvantages of offspring produced by asexual reproduction when the environment changes and in contrast what are the advantages of offspring produced by sexual reproduction when the environment changes? Put your answer here: Question 1. Describe the size difference in seeds and spores and try to explain why one is larger than the other. Table 1. Numbers of Flower Parts in Gladiolus and Snapdragon Gladiolus Snapdragon Count these flower parts: Sepals: (these are modified leaves) are the outermost (usually green) structures of the flower. Petals: Notice that the snapdragon flower has some of its petals “fused” together (a result of evolutionary adaptation). Ask your instructor to show you this. Stamens: Be sure to distinguish these from the pistil and do not include the pistil in your count. Pistil: Examine the tip of the stigma: how many parts can you see? Ovary: carpel chambers. Count the number of chambers in the ovary. (Observe a cross-section through the dissecting microscopes at the front of the classroom. Turn on the light(s) and remove the watch glasses covering the specimens to observe. Replace the watch glasses and turn off the lights when you are done.) Question 2. Typically monocots have flower parts which number in “threes” or “multiples of three.” Based on your observations which of the above plants is a monocot? Question 3. Dicots usually have their flower parts in “fours” or “fives” or some “multiple” thereof. Based on your observations which of the above species is a dicot? Question 4. Estimate the size of pine hemlock and sweet gum pollen in microns. Question 5. What kinds of organisms are likely to functions as helpers in the pollination process? Question 6. The evolution of flower structure and color is thought to reflect natural selection for more efficient pollination mechanisms. Given that different colors and scents might attract different pollinators suggest how the odd shape of the snapdragon flower might help the pollination process. Question 7. Conifers and Cycads are wind pollinated. (Note: some Flowering plants (e.g. grasses) no longer have colorful flowers because they have reverted back to using wind for pollination.) Describe a few characteristics you would expect to see in wind-pollinated plants vs. animal-pollinated plants. After pollination the pollen grain (male gametophyte) germinates and the pollen tube grows through the tissue of the style to the ovary and enters the ovule where an egg is fertilized. Question 8. It is known that many organisms or parts of organisms grow toward or away from various stimuli such as light chemicals gravity and so forth. Consider what you know about flowers and suggest a likely mechanism that might direct the growth of the pollen tube toward the ovules. Question 9. One of these seeds should separate easily into two equal halves called cotyledons. Plants with seeds having two cotyledons are called dicotyledons or “dicots” for short. Of the seeds you examine which plant is a dicot? Question 10. Those plants whose seeds do not so easily separate and have only one cotyledon are the monocotyledons or “monocots” for short. Which plant is a monocot? Question 11. How many chambers do the ovaries of the tomato and the green pepper have? Are they monocots or dicots? Question 12. What other plant foods that we eat are commonly called vegetables but are actually fruits like the tomato? Give several examples. Question 13. Does the gladiolus have parallel or net veined leaves? Go online to answer this question. Question 14. Do the snapdragons have parallel or net veined leaves? Go online to answer this question. Question 15. In the space below make you own sketch of a small section of leaf epidermis; include two stomata with their guard cells. Label all parts. Question 16. Question 17. Observe the cross section above. In the space below sketch a small section of the Syringa (lilac) leaf cross section. See Figure 4 the charts in the lab or the Internet for help. Label the following: Question 18. Question 19. Which plant grass or geranium has parallel veins in its leaves? Is this plant a monocot or a dicot? (use the internet) Question 20. Which plant has a net-like pattern in its leaves? Is this plant a monocot or a dicot? Question 21. Are these dots parts of structures which extend lengthwise through the stem? Question 23. Dicotyledons have vascular bundles in a ring. Which plant is a dicot? Table 2. Comparison of Monocot and Dicot Characteristics Characteristic Monocot Example monocot observed Dicot Example monocot observed flower parts: most common multiple (3s vs. 4s & 5s)? number of cotyledons in the seeds? type of leaf veins (net vs. parallel?) vascular bundles (scattered vs. ring?) Question 24. In the Grossmont College Wildlife Sanctuary a chaparral community the native silverback fern thrives. During what time of the year would you expect this fern to produce gametophytes (Look at the typical plant life cycle) ? Why? This question is about logic not actualy going out and looking) Question 25. For the sperm of one gametophyte to successfully find its way to the archegonium of another gametophyte certain environmental conditions must be present. Name some of these: Question 26. Both the sperm and the egg of the fern plant have the haploid (1n) number of chromosomes. Describe the chromosome number of the zygote (the fertilized egg). labels on the diagram below (Structures 1-6): sporophyte spores sporangia sorus gametophyte whether it is diploid (2n) and which is haploid (1n). Requirements: Which cells of the epidermal layer contain chloroplasts? What do you know is the function of the stomata and guard cells? How do you think the chloroplasts in the guard cells relates to this function? cuticle upper and lower epidermis stoma and guard cells palisade mesophyll cells and spongy mesophyll cells vascular tissue (veins which include xylem and phloem) intercellular space. What function do you think the palisade and spongy mesophyll tissues provide for the plant? What do the stomata do for the intercellular spaces in the mesophyll tissue? Why do you suppose that the guard cells have chloroplasts while the other epidermal cells do not? Using the wall chart in the lab and Figure 4 put the following For sporophyte and gametophyte generations be able to indicate Be able to indicate in which structures meiosis occurs. Which cells of the epidermal layer contain chloroplasts? What do you know is the function of the stomata and guard cells? How do you think the chloroplasts in the guard cells relates to this function? What function do you think the palisade and spongy mesophyll tissues provide for the plant? What do the stomata do for the intercellular spaces in the mesophyll tissue? Why do you suppose that the guard cells have chloroplasts while the other epidermal cells do not? Using the wall chart in the lab and Figure 4 put the following For sporophyte and gametophyte generations be able to indicate Be able to indicate in which structures meiosis occurs.